At work recently I found an old lens for a very old Barco projector we used long ago. The projector was one of those three internal CRT lens deals. The lens I found is a 7:1 extra long throw fixed ...

The F-number of a photographic lens is a measure of its light-gathering ability, and is expressed as its aperture diameter divided by its focal length. Lenses with low F-numbers are prized by ...

Projection lenses play a prominent role in modern society. When combined with a projector, these lenses allow people to view two-dimensional images on a screen by magnifying them and throwing them ...